


You're the Greatest Magic

by moeblobmegane



Series: ∞ Days with NagiRin [1]
Category: Free!
Genre: Fluff, M/M, Snuggling, demon!Rin, witch!Nagisa
Language: English
Status: Completed
Published: 2014-02-03
Updated: 2014-02-03
Packaged: 2018-01-11 01:31:23
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,142
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/1167004
Author URL: https://archiveofourown.org/users/moeblobmegane/pseuds/moeblobmegane
Summary: <blockquote class="userstuff">
              <p>Rin, a 17 years old demon, meets Nagisa, a witch's son, and makes the rashest decision he ever did (and the best, definitely the best)</p><p>[Rin POV, Demon!AU]</p>
            </blockquote>





	You're the Greatest Magic

" _Please?_ " The human child looked at him with bright, red eyes that seemed to look deep into his soul. Which was stupid because he was a walking soul who had no material body. Why was this boy even able to see him? "I’d really like to learn how to appear like ‘poof!’ everywhere" He insisted, tugging on Rin’s sleeves.  _Which isn’t fucking physical. What the hell is this kid?_

Rin has always been a fan of bluntness so he snapped “What the hell are you?” at the kid, not even trying to be kind. He doesn’t need to be kind. He’s a demon, for god’s sake! (Okay, that sounded like a pun but it wasn’t a pun in his head. He’s not the type to laugh at things).

"I’m…" The boy frowned and tilted his head, showing utmost confusion. "I’m Nagisa! I’m  _a Nagisa_? I’m _the only Nagisa_? Hmmm…" He seemed deep in thought as he continued to cling on Rin’s sleeves ( _that isn’t supposed to be fucking there. What the actual fuck_ ).

"You’re human?" Rin asked helpfully, because this is getting nowhere and his brilliant mind needs more clues before he can figure out why anyone can touch him.

Nagisa blinked. “Well, I am, right?” He asked back.

"You are." The demon replied slowly, trying to tug his sleeves away from the kid who had a deadly grip on him (still not a pun, goddamnit). "But you’re not  _exactly_ -"

"I know, right?!" Nagisa brightened at those words. "Maybe I can go poof! And whooosh!" His eyes shone with hope as he let go of Rin and used his hands to show different movements he wanted to do. He waved his arms around, as if he would fly. "Mom can go ‘poof!’ but she said I’m not… um, what was her word? Ah! I’m not gifted…?" He tilted his head to the right innocently, thinking deeply. "But I  _can_ be gifted! Can’t I?”

There was something about this boy. A power inside him that Rin feels but can’t see. A well he knows is there but can’t utilize just yet. He felt something tug inside him. He knew there was potential there. Nagisa may not be 'gifted', but he had something that made him much more special than any other witch. “Do you want to have a familiar?”

Eyes widening, Nagisa nodded immediately. “Would I be able to do ‘poof!’ if I have a familiar?”

Rin could feel himself regretting the choice immediately. He was young, in demon years, and he had so much time to choose. But the boy was here and Rin felt connected to him more than anything. “You would. If you train hard enough.”

"I will!" Nagisa smiled widely. "I definitely will!"

It was, perhaps, the rashest decision he has ever done. But also probably the best. ( _Definitely the best._ )

—-

The thing with having a child, a human child, as a partner, is that you need to take care of him and talk to him more than you would if your partner was, say, a bird. Or a cat. Or anything, really.

Rin was an idiot for choosing him. He didn't even need to be a familiar, didn't need to succumb to anyone else. He was powerful on his own and he needed no help. And yet...

"Rinrin!" Nagisa ran up to him with a large smile and wide, begging eyes.  _Here we go again_. "Can you teach me how to go ‘whoooosh’ one more time?" He clung to Rin’s arm and tugged repeatedly. "Please?"

"We have rules against using too much magic, right?" Rin asked in his most I-am-the-boss-here voice. It always fails (because Nagisa is the boss) but at least he tries.

"But I can still do it!" Nagisa persisted. "The other demon said I had more… um r- raw? Raw power? I have more of that than anyone else he knows!"

Rin frowned, closing his eyes as he tried to contain his emotions. “You talked to  _Haru_?” Of all people, Nanase Haruka? Rin's rival for life?

Nagisa nodded happily. “Because he’s the coolest!” His eyes shone with complete admiration for the other demon.

"Cooler than  _anyone_?" Rin asked, scrunching up his nose and glancing at the younger boy with disdain.

"Yep!" Nagisa replied with the biggest smile he could make. "Haru-chan does the best ‘poof’ magic!"

Rin groaned before sighing heavily. “You know what? I’m tired. Really tired.” He explained slowly. “I need to rest. You should, too. Your sisters must be looking for you.”

Nagisa pouted, not letting go of Rin’s arms. “But my sisters would just put a curse on me and make me do weird stuff just because they’re angry I got a cool familiar before they could.”

' _Huh. So I'm just **cool**. And Haru is the  **coolest**. This fucking kid_.' Rin sighed and knelt down. “Would you like me to teach you a defense charm?”

Nagisa’s eyes twinkled with curiosity. “Yes!”

At the end of the day, no matter what he is, Nagisa really always does win.

—-

Another bad thing about having a human child as a partner is the fact that they grow up fast. Faster than demons. They change shape almost constantly, confusing Rin more than he already was.

And they also learn. Faster than any species, he thinks. They talk to everyone, they walk everywhere and they touch so many things. They record everything inside their little, mortal minds and keep them safe in their souls.

Even among humans, Nagisa was different. He learned much, much faster. The raw potential soon became full-blown powers. He grew taller, moved faster, became much more powerful than Rin initially thought. The young child he took in as his partner became a young man in just a blink of an eye.

 

 

Rin woke up one day and saw Nagisa, 17 years old and all grown up now, appearing with a ‘poof’ on his door step. The human then smiled and snapped his fingers and appeared on the bed, snuggling on the blanket Rin had left there just a second ago. “Good morning.” The demon greeted, trying not to be distracted by how Nagisa sniffed at the blanket and rolled around the bed as if marking territory. (That was wolf behavior, and last time he checked Nagisa was still 100% human).

Nagisa sat up and saluted, grinning. “Hazuki Nagisa reporting for duty, sir!” He intoned, making Rin think that he probably saw some kind of stupid movie again while taking a stroll on the urban cities.

"It’s too fucking early for this" Rin groaned, sliding back to his bed with ease, putting a casual arm around Nagisa’s waist as he lied down. He pulled in and closed his eyes, calming down and feeling sleepy almost immediately. "Mmmm… Let’s just…"

Giggling a bit, Nagisa squirmed around until he was facing Rin. He rubbed his nose on the older boy’s chest, taking an obvious whiff. “Why do you always smell like catnip? Are you secretly a cat?” He asked playfully but curiously.

"Maybe I turn into a cat sometimes. Who knows." Rin replied with a shrug, not even opening his eyes as he laced his fingers on Nagisa’s golden hair. He’s always thought they might be related to his magic. They looked too beautiful to be normal human hair. He started playing around with it, combing it absentmindedly as he drifted back to sleep.

"You don’t run off to become someone else’s familiar though, do you?" This time, there was a childish tone in it. They both knew Nagisa wasn’t being serious (he was too smart for that).

Rin would have rolled his eyes if he actually had them open. “Sure I do. I whore myself out to other witches. All the fucking time.” He yawned and stilled his hand still tangled in his partner’s hair.

Nagisa laughed at that, snuggling closer, placing his other hand on Rin’s back and massaging it lightly. “Nah,” He whispered, voice soft against Rin’s chest. “You’re too much of a princess that no one would take you in.”

"Princess?" Rin lightly shoved at him, opening one eye to look at the boy’s giggling face. "How the fuck am I a princess?"

Rolling his eyes, Nagisa tugged back again until they were back to their old position. His breath is warm against Rin’s chest, as if he was talking straight to Rin’s non-existent heart. “A very, very angry one with a potty mouth. But still a bratty _princess_.”

"That doesn’t even make sense." Rin growled, but it was more like a sleepy reaction from a cub than an actual threatening growl.

"It does, to me." Nagisa shrugged. He rested his forehead on Rin’s collarbone, breathing in quietly. "Now are you going to sleep again or would you train me now? You’re really talkative, somehow."

"Shut up and let me sleep some more, damnit." Rin replied halfheartedly, already halfway asleep. There was just something calming, even disarming, about the way Nagisa rests against him. It felt like home.

 _Nagisa is the most powerful magic Rin has ever known_.

—-

But sometimes Rin forgets.

Nagisa is beautiful and powerful and wise. He’s energetic and happy like a child, but also mature and understanding like an adult. He’s perfection in Rin’s eyes.

But he’s human.

A powerful witch, yes. But human. With human flesh, human bones, parts that doesn’t heal immediately when wounded. Parts that bleed out crimson when attacked. Parts that might just prove fatal.

"Fuck, fuck, _fuck_ …" Rin held on to his hand, gritting his teeth and hating how pale Nagisa looked. "You’re healing yourself, right? You’re- _fuck_ , don’t die on me. You can’t  _die_  on me. You’re just a  _kid_ , Nagisa. You can’t die right now." He tightened his grip on his hand, willing his own powers to drift on to Nagisa to help heal the wounds. "You can’t just-" He was crying now, choking on his words. "You can’t just fucking leave me here."

"It’s okay, Rinrin." As per usual, Nagisa was the calm one. Even when at death’s door, he was the one smiling and calming Rin down. "You taught me the healing spell, right?" He placed a gentle hand on Rin’s cheek, thumb tracing the trail of his tears. "I’ll be fine."

'You're not healing fast enough!' Rin wanted to shout. But instead, he closed his eyes and concentrated on driving everything he had to his partner. “ _You'll be fine_.” Rin quietly affirmed, wishing with all his heart that this time too, Nagisa would win.

 

—-

Rin woke up with warmth pressed against him, the familiar warmth that could only mean Nagisa had sneaked into his bed again. “Mmm” He moaned sleepily, placing a hand on the human’s tiny back. “Why are you-” Memories flooded back his mind, and in a second, he’s sat up on his bed with wide eyes. “Nagisa!”

"Yeah…?" Nagisa sleepily answered. He was shirtless, revealing the bandages around his whole torso. He looked fine now, but still hurt. Rin felt as much. " ‘m fine now." He murmured, tugging at Rin’s arm to make him lie down again.

"Go back to the healer, damnit." He hissed, even though he missed this warmth, missed it so much he wanted to curl up and sleep again. He had trouble sleeping this whole week, always being woken up by nightmares about Nagisa’s death. "You need rest." He said with definite worry.

"I’m resting, though." Nagisa replied, still not willing to even open his eyes. "You’re not listening to the patient, you ungrateful little kitten." He pouted, sounding like he was sleeptalking more than anything. "Go back to sleep." He used his authoritative voice. His own version of the I-am-boss voice.

Which, sadly, has magic in it. And is most potent against his own familiar. Especially a sleepy, very willing familiar.

Rin slid back down and placed his hand on the small of his back again. “Tsk,” He still acted like this was such a hassle though. For his own pride.

"You need sleep," Nagisa murmured, softly this time. There was a hint of worry too, like he was the one who should worry instead of Rin. "I’m okay now."

"You’d be better in the healer’s house." Rin insisted, but his heart wasn’t in it. Having his partner so close made him relax more than anything. And he  _did_  need the sleep. He wasn’t complaining about that.

"You’re my healer." Nagisa replied, a laugh escaping just after the sentence. It was a cheesy pick-up line and they both knew it.

Rin rolled his eyes and placed his nose down on Nagisa’s hair, breathing in and letting power flow from his arms to Nagisa’s back. “Then shut up and let me heal you.”

Nagisa’s tinkling laugh filled the house again, and Rin thought that, even though it must sound like a cheesy pick-up line, the boy was his healer too.


End file.
